They were booked at Marin County Jail on suspicion of involuntary manslaughter. Their bail was set at $75,000 each.

The baby, whose name was not released, was found unresponsive at the center on Las Ovejas Avenue on the afternoon of Oct. 23, authorities said. Firefighters took the boy to Kaiser Permanente Medical Center in San Rafael, where he was pronounced dead.

The coroner concluded Monday that the boy died of asphyxia by suffocation because of obstruction of the external airway by bedding, authorities said. The death was ruled accidental.

The infant's death is also being investigated by the state's community care licensing division.

The center is a licensed infant day care center capable of caring for 24 children, state records show.

Gil told The Chronicle last week that the boy had been asleep for several hours and never woke up. "I hope you know how I feel," Gil said.